This invention relates generally to an automotive alternator system, and more specifically to a voltage regulator for r such a system that advantageously reduces the number of external connections between the voltage regulator and the various automotive systems.
Voltage regulator controlled automotive recharging systems are commonly used to keep an automotive storage battery at full charge and to provide sufficient electrical power for the operation of the various automotive electrical accessories. Conventionally, an alternator provides a rectified output current as it is driven by a belt and pulley arrangement coupled to the automobile internal combustion engine. The alternator comprises a field winding, a 3-phase stator winding, and a full-wave diode rectifier for converting the poly-phase AC output of the windings to a DC voltage. The alternator operation is controlled through a closed feedback system by the voltage regulator, which senses the battery voltage and controls the alternator field coil excitation in response thereto attempts to maintain a full charge on the battery. An indicator lamp typically provides an indication to the automobile operator of the absence of an alternator output voltage and in this way alerts the operator to a malfunction in the electrical system.
In some charging systems, a continuous DC field coil excitation current is provided. Alternatively, switching-based voltage regulators operate in an on/off mode wherein a switching device is utilized to alternately stepwise excite the alternator field coil between full and zero excitation values. In this system, the rate of the stepwise excitation and the duration of the excitation periods are varied in accordance with engine speed and the resistive load placed upon the battery. Generally, the alternator is defined as that device producing a polyphase output current. When an alternator is coupled with a voltage regulator, the device is referred to as a generator, which supplies a DC current for charging the automobile battery.
In today""s automobile market, the alternator and the attendant voltage regulator are usually supplied by an automotive parts vendor to the automobile manufacturers. There are many different automobile types and also many different electrical/charging systems among those automobile types. Although there is some commonality between electrical/charging systems employed in each automobile, many also have unique requirements in the interface between the automobile engine control systems and the alternator and voltage regulator. As a result, alternator/voltage regulator vendors are required to supply several unique products to interface with the wide variety of automobile control systems. Designing, manufacturing and assuring that sufficient inventory exists for each of the many alternator/regulator models results in unnecessary expense for the alternator vendor, which is generally passed through to the automobile manufacturer and then to the automobile purchaser.
The present invention overcomes the disadvantages associated with the supply of several different generator (or alternator/voltage regulator combination) models. In particular, by interconnecting certain voltage regulator terminals according to the teachings of the present invention, a single generator model can be employed in several different automobile systems. In the prior art, several different generator systems are required, dependent on the interface requirements of the electrical charging system of the automobile.